Field of the Disclosure
The present disclosure relates to a control apparatus, a control method, and a program for an image processing apparatus having a plurality of image units of processing.
Description of the Related Art
There is known a method in a printing apparatus such as a printer has been known which includes dividing a print job, wherein the divided printed jobs are distributed to and processed in parallel by a plurality of rasterizing devices for increasing the speed of the rasterization of the print job. For example, the method may include predicting a rasterizing time for a print job, dividing the print job and distributing the divided print jobs to rasterizing devices such that the rasterizing processes in the rasterizing devices can complete appropriately at the same time. However, accurate prediction of the rasterizing times for a print job is difficult, and a prediction error may result in differences in time of completion between rasterizing devices even though the print jobs have been distributed such that the rasterization processes of the divided print jobs can complete approximately at the same time. FIG. 16A illustrates an exemplary time chart for rasterizing devices. As illustrated in FIG. 16A, when a difference occurs between times of completion of the rasterizing processes, the longest completion time of the rasterizing device B is determined as the rasterization completion time of the whole print job. In a case where print jobs are sequentially processed, prediction errors as described above may be accumulated, resulting in large differences in rasterization completion time between the rasterizing devices, as illustrated in FIG. 16B. Therefore, such a distribution method based on only the predicted rasterizing times may not sufficiently increase the speed of the rasterization of a print job.
Accordingly, a method has been proposed (see Japanese Patent Laid-Open No. 2004-164445) which determines a distribution ratio based on CPU types, CPU activity ratios and performances and resource availability such as a free memory space of devices.
Here, in some cases, a series of processes such as a process for receiving job data, an image correction process, an RIP processing of, for example, PDL, a process of rotating and pagination of bitmap data, and a process for transmitting the bitmap data may be sequentially executed for each processing unit such as a page within rasterizing devices. Then, as illustrated in FIGS. 17A to 17C, these processes may be concurrently executed on different pages in parallel. FIGS. 17A to 17C illustrate time charts for one rasterizing unit. As illustrated in FIGS. 17A to 17C, in one rasterizing unit, different types of processes but not the same type of processes are executed on a plurality of pages in parallel. In other words, one receiving process and another receiving process are not allowed to be executed in parallel. One RIP process and another RIP process are not executed in parallel. Similarly, the rotation/pagination process and another rotation/pagination process and one transmitting process and another transmitting process are not executed in parallel. The image correction process is executed only after the receiving process, the RIP process after the image correction process, the rotation/pagination process after the RIP process, and the transmitting process after the rotation/pagination process. When the aforementioned processes are executed, the activity ratios of resources such as CPUs and memory depend on the concurrency of the processes, instead of the rasterizing times. Thus, a higher activity ratio of a resource may not necessarily result in a longer rasterizing time. As illustrated in FIG. 17B, when processing a print job with a high rasterization load, the processes may take a longer time and consequently a longer rasterizing time while the concurrency of the processes may decrease, and the activity ratios of resources may decrease. Conversely, when processing a print job with a lower rasterization load, the processes may take a shorter time and consequently a shorter rasterizing time while the concurrency of the processes may increase, and the activity ratios of resources may increase. In other words, the time period increases in which the activity ratio of the resource for the rasterizing units performing the processes illustrated in FIG. 17C is higher than the activity ratio of the resource for the rasterizing units performing the processes illustrated in FIG. 17B. Therefore, according to the method disclosed in Japanese Patent Laid-Open No. 2004-164445, the distribution ratios for the rasterizing units in FIG. 17B are set lower than the distribution ratio for the rasterizing units in FIG. 17C. As a result, with distribution of jobs based on the activity ratios of a resource as in Japanese Patent Laid-Open No. 2004-164445, it is not possible to make the difference in the time of completion of rasterization as small as possible.